Heyo Safe Networking community, I need some assistance...again.

After saving my PC from the clutches of Virtumonde, I'm finally ready to install Windows XP SP2. Unfortunately, every attempt at an update to SP2 results in a failure because you first need to install Windows Installer 3.1...which for some reason won't install on my PC.

Has anyone else overcome this frustrating problem? Does anyone have any advice as to what I can do?

Thanks in advance.